1. Field of the Invention
The present invention is directed to an electrical control circuit for providing an analog voltage signal to an electronic transmission controller for a hydrostatic transmission.
2. Description of the Prior Art
Hydrostatic transmissions are becoming increasingly common in off road work vehicles. Electronic transmission controllers have been used to control the operation of the hydrostatic transmission. These controllers receive an analog voltage signal from the operator to control the output of the transmission. In a system currently marketed by the assignee of the present invention, the system uses two levers to control the operation of the transmission. The first lever is used to control steering and the forward and reverse movement of the vehicle. The maximum desired speed of the vehicle is controlled by a separate lever.
Single lever shift levers for off road work vehicles have been proposed which have a knob that can be rotated to signal different speed ratios. The knob may also be provided with a rocker switch which is used to shift the transmission between forward and reverse, see U.S. Pat. No. 4,360,718. In addition, a steering lever for an off road work vehicle has also been proposed having keys for shifting the transmission into forward and reverse. Other keys are provided for higher or lower speed levels, see U.S. Pat. No. 5,566,586.